In a photoresist process, one of the semiconductor manufacturing processes, a resist coated on a surface of a semiconductor wafer (hereinafter, referred to as a wafer) is exposed to light by employing a specified pattern and then developed, thereby forming a resist pattern on the surface of the wafer. Such process is generally carried out by using a system in which an exposure device is combined with a coating/developing apparatus for coating and developing a resist.
As illustrated in FIGS. 16A to 16C, for example, in a conventional developing apparatus, a wafer W is horizontally kept on a substrate supporting unit 1, and a developer nozzle 11 having a small injection hole is provided at a position slightly upwardly separated from a surface of the wafer W. By moving the developer nozzle 11 discharging a developer along a radial direction of the wafer W while the wafer W being rotated about a vertical axis, the developer is spirally sprayed on the surface of the wafer W (FIG. 16A). Further, after a developer 12 is sprayed on the surface of the wafer W, the wafer W is stopped from being rotated and developed for a predetermined time period, e.g., 60 seconds (FIG. 16B). Then, a rinse 14, e.g., deionized water, is supplied through a rinse nozzle 13 to a central portion of the wafer W (FIG. 16C). In this way, the insoluble resist portions in the developer are left intact, thereby producing a specific resist pattern.
Moreover, there has been known a technique: a developer is supplied to a wafer W whose surface is coated with a resist having a pattern portion extending in a direction intersecting a rotational direction of the wafer W that is rotating about a vertical axis, and the wafer W is rotated forwardly and backwardly, whereby a resist layer on a sidewall surface of the pattern, that has to be eliminated, is made to be surely removed (see, for example, Japanese Patent Laid-open Publication Nos. 2002-075854 and 2003-272988).
However, the aforementioned developing method has following drawbacks. Since the developer is supplied while the wafer W is rotated about the vertical axis, the developer flows outwardly from the central portion along a parabolic trace in a direction opposite to that of the rotation of the wafer W on the surface of the wafer W. Depending on a shape or layout of a pattern transcribed on a resist by an exposure, when the pattern begins to be revealed due to a contact with the developer, the pattern may hinder the flow of the solution. Accordingly, the developer may not uniformly reach all over the pattern, especially over a downstream side portion of the pattern, thereby deteriorating the accuracy in realizing a precise line width. But, since a nonsmooth solution flow causes only a very slight deterioration in the accuracy in realizing a precise line width and, thus, it was not conventionally considered to be much a problem. However, along with a recent trend of a pattern's miniaturization, it becomes imperative to make the solution flow smooth to achieve a higher degree of accuracy in realizing a precise line width.
Hereinafter, there will be described an exemplary pattern, which is subject to a nonsmooth solution flow. When patterns of multiple chips are transcribed on a surface of a wafer W by an exposure, the patterns are successively transcribed, for example, by moving the wafer W with respect to an exposure device. Thus, the multiple chips are transcribed on the surface of the wafer W along a same direction. The patterns of the chips vary depending on purposes. However, as schematically illustrated in FIG. 17, the pattern of a single chip generally includes a pattern portion 15 and a non-pattern portion 16. In this case, even though the developer is supplied to the wafer W, a resist of a non-pattern portion remains without being dissolved. Accordingly, if the residual resist is positioned at an upstream side of a developer flow, the flow toward a downstream side pattern portion thereof will be hindered.